As society has become increasingly information-oriented in recent years, the amount of data managed by corporations has shown a steady increase. On the other hand, for such purposes as cutting management costs of IT systems, there is an emerging trend where private corporations are beginning to opt to lease IT systems from vendors specializing in the management and provision of IT systems, instead of owning their own IT systems. Along therewith, data managed by corporations are starting to be aggregated within IT systems owned by vendors specializing in the management and provision of IT systems. In order to enable the accumulation of such vast amounts of aggregated data, storage systems included in IT systems are becoming ever larger in scale.
With current IT systems, if, for example, performance drops at a path between a given I/F of a host device and a given I/F of a switch device, the band used at this path is changed, thereby enabling QoS control. By way of example, Patent Literature 1 discloses switching FCoE (Fibre Channel over Ethernet (Ethernet is a registered trademark)) paths based on data transfer amount.